.. index:: pair: struct; dnnl::primitive_desc
.. _doxid-structdnnl_1_1primitive__desc:

struct dnnl::primitive_desc
===========================

.. toctree::
	:hidden:

Overview
~~~~~~~~

A base class for descriptors of all primitives that have an operation descriptor and that support iteration over multiple implementations. :ref:`More...<details-structdnnl_1_1primitive__desc>`


.. ref-code-block:: cpp
	:class: doxyrest-overview-code-block

	#include <dnnl.hpp>
	
	struct primitive_desc: public :ref:`dnnl::primitive_desc_base<doxid-structdnnl_1_1primitive__desc__base>`
	{
		// construction
	
		:target:`primitive_desc<doxid-structdnnl_1_1primitive__desc_1ae5452031cfd89bda919543dace0ff7bd>`();
	
		:ref:`primitive_desc<doxid-structdnnl_1_1primitive__desc_1a1d5b57166120c0204ee4bb86d310b9ab>`(
			:ref:`const_dnnl_op_desc_t<doxid-group__dnnl__api__primitives__common_1ga68197f349eb0876085adfb385d8932de>` desc,
			const primitive_attr* attr,
			const :ref:`engine<doxid-structdnnl_1_1engine>`& aengine,
			:ref:`const_dnnl_primitive_desc_t<doxid-group__dnnl__api__primitives__common_1gab604e76e39a791e855bc6bb4ee13c63f>` hint_fwd_pd,
			bool allow_empty = false
			);

		// methods
	
		bool :ref:`next_impl<doxid-structdnnl_1_1primitive__desc_1a841df469ca54c3de2d233e46f48322b2>`();
		:ref:`primitive_desc_base<doxid-structdnnl_1_1primitive__desc_1a27780142d0880bb0ca678f7c5a1845b9>`();
		:ref:`primitive_desc_base<doxid-structdnnl_1_1primitive__desc_1aae07f2f06d74537546c3056bd305dfbe>`();
		:ref:`primitive_desc_base<doxid-structdnnl_1_1primitive__desc_1af4eac2eea0fd4eb37c0c90ead14ad52b>`();
		:ref:`primitive_desc_base<doxid-structdnnl_1_1primitive__desc_1aa4853f3190cac45b653e510b6eeed97a>`();
	};

	// direct descendants

	struct :ref:`primitive_desc<doxid-structdnnl_1_1batch__normalization__backward_1_1primitive__desc>`;
	struct :ref:`primitive_desc<doxid-structdnnl_1_1batch__normalization__forward_1_1primitive__desc>`;
	struct :ref:`primitive_desc<doxid-structdnnl_1_1binary_1_1primitive__desc>`;
	struct :ref:`primitive_desc<doxid-structdnnl_1_1convolution__backward__data_1_1primitive__desc>`;
	struct :ref:`primitive_desc<doxid-structdnnl_1_1convolution__backward__weights_1_1primitive__desc>`;
	struct :ref:`primitive_desc<doxid-structdnnl_1_1convolution__forward_1_1primitive__desc>`;
	struct :ref:`primitive_desc<doxid-structdnnl_1_1deconvolution__backward__data_1_1primitive__desc>`;
	struct :ref:`primitive_desc<doxid-structdnnl_1_1deconvolution__backward__weights_1_1primitive__desc>`;
	struct :ref:`primitive_desc<doxid-structdnnl_1_1deconvolution__forward_1_1primitive__desc>`;
	struct :ref:`primitive_desc<doxid-structdnnl_1_1eltwise__backward_1_1primitive__desc>`;
	struct :ref:`primitive_desc<doxid-structdnnl_1_1eltwise__forward_1_1primitive__desc>`;
	struct :ref:`primitive_desc<doxid-structdnnl_1_1inner__product__backward__data_1_1primitive__desc>`;
	struct :ref:`primitive_desc<doxid-structdnnl_1_1inner__product__backward__weights_1_1primitive__desc>`;
	struct :ref:`primitive_desc<doxid-structdnnl_1_1inner__product__forward_1_1primitive__desc>`;
	struct :ref:`primitive_desc<doxid-structdnnl_1_1layer__normalization__backward_1_1primitive__desc>`;
	struct :ref:`primitive_desc<doxid-structdnnl_1_1layer__normalization__forward_1_1primitive__desc>`;
	struct :ref:`primitive_desc<doxid-structdnnl_1_1logsoftmax__backward_1_1primitive__desc>`;
	struct :ref:`primitive_desc<doxid-structdnnl_1_1logsoftmax__forward_1_1primitive__desc>`;
	struct :ref:`primitive_desc<doxid-structdnnl_1_1lrn__backward_1_1primitive__desc>`;
	struct :ref:`primitive_desc<doxid-structdnnl_1_1lrn__forward_1_1primitive__desc>`;
	struct :ref:`primitive_desc<doxid-structdnnl_1_1matmul_1_1primitive__desc>`;
	struct :ref:`primitive_desc<doxid-structdnnl_1_1pooling__backward_1_1primitive__desc>`;
	struct :ref:`primitive_desc<doxid-structdnnl_1_1pooling__forward_1_1primitive__desc>`;
	struct :ref:`primitive_desc<doxid-structdnnl_1_1pooling__v2__backward_1_1primitive__desc>`;
	struct :ref:`primitive_desc<doxid-structdnnl_1_1pooling__v2__forward_1_1primitive__desc>`;
	struct :ref:`primitive_desc<doxid-structdnnl_1_1prelu__backward_1_1primitive__desc>`;
	struct :ref:`primitive_desc<doxid-structdnnl_1_1prelu__forward_1_1primitive__desc>`;
	struct :ref:`primitive_desc<doxid-structdnnl_1_1reduction_1_1primitive__desc>`;
	struct :ref:`primitive_desc<doxid-structdnnl_1_1resampling__backward_1_1primitive__desc>`;
	struct :ref:`primitive_desc<doxid-structdnnl_1_1resampling__forward_1_1primitive__desc>`;
	struct :ref:`rnn_primitive_desc_base<doxid-structdnnl_1_1rnn__primitive__desc__base>`;
	struct :ref:`primitive_desc<doxid-structdnnl_1_1shuffle__backward_1_1primitive__desc>`;
	struct :ref:`primitive_desc<doxid-structdnnl_1_1shuffle__forward_1_1primitive__desc>`;
	struct :ref:`primitive_desc<doxid-structdnnl_1_1softmax__backward_1_1primitive__desc>`;
	struct :ref:`primitive_desc<doxid-structdnnl_1_1softmax__forward_1_1primitive__desc>`;

Inherited Members
-----------------

.. ref-code-block:: cpp
	:class: doxyrest-overview-inherited-code-block

	public:
		// methods
	
		:ref:`handle<doxid-structdnnl_1_1handle>`<T, traits>& :ref:`operator =<doxid-structdnnl_1_1handle_1a4ad1ff54e4aafeb560a869c49aa20b52>` (const :ref:`handle<doxid-structdnnl_1_1handle>`<T, traits>&);
		:ref:`handle<doxid-structdnnl_1_1handle>`<T, traits>& :ref:`operator =<doxid-structdnnl_1_1handle_1af3f85524f3d83abdd4917b46ce23e727>` (:ref:`handle<doxid-structdnnl_1_1handle>`<T, traits>&&);
		void :ref:`reset<doxid-structdnnl_1_1handle_1a8862ef3d31c3b19bd88395e0b1373909>`(T t, bool weak = false);
		T :ref:`get<doxid-structdnnl_1_1handle_1a2208243e1d147a0be9da87fff46ced7e>`(bool allow_empty = false) const;
		:ref:`operator T<doxid-structdnnl_1_1handle_1a498e45a0937a32367b400b09dbc3dac3>` () const;
		:ref:`operator bool<doxid-structdnnl_1_1handle_1ad14e2635ad97d873f0114ed77c1f55d5>` () const;
		bool :ref:`operator ==<doxid-structdnnl_1_1handle_1a069b5ea2a2c13fc4ebefd4fb51d0899e>` (const :ref:`handle<doxid-structdnnl_1_1handle>`<T, traits>& other) const;
		bool :ref:`operator !=<doxid-structdnnl_1_1handle_1a1895f4cd3fc3eca7560756c0c508e5ab>` (const :ref:`handle<doxid-structdnnl_1_1handle>`& other) const;
		:ref:`engine<doxid-structdnnl_1_1engine>` :ref:`get_engine<doxid-structdnnl_1_1primitive__desc__base_1a32f7477c79e715a341bb9127df521fbc>`() const;
		const char* :ref:`impl_info_str<doxid-structdnnl_1_1primitive__desc__base_1ae680492d4e4b16a938cfc051e5c906be>`() const;
		:ref:`memory::dim<doxid-structdnnl_1_1memory_1a6ad818e4699872cc913474fa5f122cd5>` :ref:`query_s64<doxid-structdnnl_1_1primitive__desc__base_1acbedc4257eaa26f868356f9f594a856a>`(:ref:`query<doxid-group__dnnl__api__primitives__common_1ga94efdd650364f4d9776cfb9b711cbdc1>` what) const;
		:ref:`memory::desc<doxid-structdnnl_1_1memory_1_1desc>` :ref:`query_md<doxid-structdnnl_1_1primitive__desc__base_1a35d24b553ba6aa807516e9470fdd7d16>`(:ref:`query<doxid-group__dnnl__api__primitives__common_1ga94efdd650364f4d9776cfb9b711cbdc1>` what, int idx = 0) const;
		:ref:`memory::desc<doxid-structdnnl_1_1memory_1_1desc>` :ref:`src_desc<doxid-structdnnl_1_1primitive__desc__base_1af42e791f493e636c086e13c6d4c06b43>`(int idx) const;
		:ref:`memory::desc<doxid-structdnnl_1_1memory_1_1desc>` :ref:`dst_desc<doxid-structdnnl_1_1primitive__desc__base_1a495ee7c8e1ec3eab35f6329fdcd352bb>`(int idx) const;
		:ref:`memory::desc<doxid-structdnnl_1_1memory_1_1desc>` :ref:`weights_desc<doxid-structdnnl_1_1primitive__desc__base_1acb13d08987cca8d8f05ec4858fa61fb4>`(int idx) const;
		:ref:`memory::desc<doxid-structdnnl_1_1memory_1_1desc>` :ref:`diff_src_desc<doxid-structdnnl_1_1primitive__desc__base_1a733e6ff4e78a758e69ae6232e8955871>`(int idx) const;
		:ref:`memory::desc<doxid-structdnnl_1_1memory_1_1desc>` :ref:`diff_dst_desc<doxid-structdnnl_1_1primitive__desc__base_1a60f17d04c493c42e4a50ad5feff5c8ca>`(int idx) const;
		:ref:`memory::desc<doxid-structdnnl_1_1memory_1_1desc>` :ref:`diff_weights_desc<doxid-structdnnl_1_1primitive__desc__base_1a192f7b334efac9a5ac20344a76d4d552>`(int idx) const;
		:ref:`memory::desc<doxid-structdnnl_1_1memory_1_1desc>` :ref:`src_desc<doxid-structdnnl_1_1primitive__desc__base_1af48dcff294cadb2916fd784b8474d221>`() const;
		:ref:`memory::desc<doxid-structdnnl_1_1memory_1_1desc>` :ref:`dst_desc<doxid-structdnnl_1_1primitive__desc__base_1addbec977643a7900f4156f7aab3fb4db>`() const;
		:ref:`memory::desc<doxid-structdnnl_1_1memory_1_1desc>` :ref:`weights_desc<doxid-structdnnl_1_1primitive__desc__base_1a93f0904566b399874c47b3b1ad3d1495>`() const;
		:ref:`memory::desc<doxid-structdnnl_1_1memory_1_1desc>` :ref:`diff_src_desc<doxid-structdnnl_1_1primitive__desc__base_1ab4268c6bb70dd6c22de43141cc301b77>`() const;
		:ref:`memory::desc<doxid-structdnnl_1_1memory_1_1desc>` :ref:`diff_dst_desc<doxid-structdnnl_1_1primitive__desc__base_1a6b9fb7da987329256c04db6ecbb9dc36>`() const;
		:ref:`memory::desc<doxid-structdnnl_1_1memory_1_1desc>` :ref:`diff_weights_desc<doxid-structdnnl_1_1primitive__desc__base_1af51378982968e2b4f7abb6a32acfb0af>`() const;
		:ref:`memory::desc<doxid-structdnnl_1_1memory_1_1desc>` :ref:`workspace_desc<doxid-structdnnl_1_1primitive__desc__base_1ad26f416a149cb44cc5cfc130012c614e>`() const;
		:ref:`memory::desc<doxid-structdnnl_1_1memory_1_1desc>` :ref:`scratchpad_desc<doxid-structdnnl_1_1primitive__desc__base_1a6238358ec03afd57fb20dffa65b48d2f>`() const;
		:ref:`engine<doxid-structdnnl_1_1engine>` :ref:`scratchpad_engine<doxid-structdnnl_1_1primitive__desc__base_1ad4079e0891373bd2dc841f3f94cf47ed>`() const;
		primitive_attr :ref:`get_primitive_attr<doxid-structdnnl_1_1primitive__desc__base_1a0ef600ea3666f0fd93c9c5d112aaf05c>`() const;
		:ref:`dnnl::primitive::kind<doxid-structdnnl_1_1primitive_1ad1ec93215a0cf3aa0a32bae0c2cd9169>` :ref:`get_kind<doxid-structdnnl_1_1primitive__desc__base_1a663f3511855bfc2625476019321c909d>`() const;

.. _details-structdnnl_1_1primitive__desc:

Detailed Documentation
~~~~~~~~~~~~~~~~~~~~~~

A base class for descriptors of all primitives that have an operation descriptor and that support iteration over multiple implementations.

Construction
------------

.. index:: pair: function; primitive_desc
.. _doxid-structdnnl_1_1primitive__desc_1a1d5b57166120c0204ee4bb86d310b9ab:

.. ref-code-block:: cpp
	:class: doxyrest-title-code-block

	primitive_desc(
		:ref:`const_dnnl_op_desc_t<doxid-group__dnnl__api__primitives__common_1ga68197f349eb0876085adfb385d8932de>` desc,
		const primitive_attr* attr,
		const :ref:`engine<doxid-structdnnl_1_1engine>`& aengine,
		:ref:`const_dnnl_primitive_desc_t<doxid-group__dnnl__api__primitives__common_1gab604e76e39a791e855bc6bb4ee13c63f>` hint_fwd_pd,
		bool allow_empty = false
		)

Constructs a primitive descriptor.

.. note:: 

   If ``allow_empty`` is true, the constructor does not throw if a primitive descriptor cannot be created. But calling :ref:`next_impl() <doxid-structdnnl_1_1primitive__desc_1a841df469ca54c3de2d233e46f48322b2>` in this case will throw.
   
   

.. note:: 

   This is a low-level implementation detail that is typically not needed in application code.



.. rubric:: Parameters:

.. list-table::
	:widths: 20 80

	*
		- desc

		- Constant C API operation descriptor.

	*
		- attr

		- Pointer to primitive attributes. It is safe to pass nullptr to indicate absence of attributes.

	*
		- aengine

		- Engine to use.

	*
		- hint_fwd_pd

		- C API primitive descriptor for a forward propagation primitive. It is used as a hint for deciding which memory format to use for backward propagation or weights gradient.

	*
		- allow_empty

		- A flag signifying whether construction is allowed to fail without throwing an exception. In this case an empty object will be produced. This flag is optional and defaults to false.

Methods
-------

.. index:: pair: function; next_impl
.. _doxid-structdnnl_1_1primitive__desc_1a841df469ca54c3de2d233e46f48322b2:

.. ref-code-block:: cpp
	:class: doxyrest-title-code-block

	bool next_impl()

Advances the primitive iterator to the next implementation.



.. rubric:: Returns:

``true`` on success, and ``false`` if the last implementation reached, and the primitive descriptor itself is kept unchanged

.. index:: pair: function; primitive_desc_base
.. _doxid-structdnnl_1_1primitive__desc_1a27780142d0880bb0ca678f7c5a1845b9:

.. ref-code-block:: cpp
	:class: doxyrest-title-code-block

	primitive_desc_base()

Default constructor. Produces an empty object.

.. index:: pair: function; primitive_desc_base
.. _doxid-structdnnl_1_1primitive__desc_1aae07f2f06d74537546c3056bd305dfbe:

.. ref-code-block:: cpp
	:class: doxyrest-title-code-block

	primitive_desc_base()

Constructs a primitive descriptor base object from a clone of a C API primitive descriptor after verifying that it is what the caller expects.

.. note:: 

   The ``prim_kind`` should map to a primitive that does not have different values of propagation kind (e.g. :ref:`dnnl::binary <doxid-structdnnl_1_1binary>`).
   
   

.. note:: 

   Primitive descriptor base constructed this way does not support :ref:`next_impl() <doxid-structdnnl_1_1primitive__desc_1a841df469ca54c3de2d233e46f48322b2>` (will throw).



.. rubric:: Parameters:

.. list-table::
	:widths: 20 80

	*
		- pd

		- C API primitive descriptor to clone.

	*
		- prim_kind

		- Expected primitive kind.

.. index:: pair: function; primitive_desc_base
.. _doxid-structdnnl_1_1primitive__desc_1af4eac2eea0fd4eb37c0c90ead14ad52b:

.. ref-code-block:: cpp
	:class: doxyrest-title-code-block

	primitive_desc_base()

Constructs a primitive descriptor base object from a clone of a C API primitive descriptor after verifying that it is what the caller expects.

.. note:: 

   Primitive descriptor base constructed this way does not support :ref:`next_impl() <doxid-structdnnl_1_1primitive__desc_1a841df469ca54c3de2d233e46f48322b2>` (will throw).



.. rubric:: Parameters:

.. list-table::
	:widths: 20 80

	*
		- pd

		- C API primitive descriptor to clone.

	*
		- prim_kind

		- Expected primitive kind.

	*
		- aprop_kind

		- Expected propagation kind.

.. index:: pair: function; primitive_desc_base
.. _doxid-structdnnl_1_1primitive__desc_1aa4853f3190cac45b653e510b6eeed97a:

.. ref-code-block:: cpp
	:class: doxyrest-title-code-block

	primitive_desc_base()

Constructs a primitive descriptor base object from a clone of a C API primitive descriptor after verifying that it is what the caller expects.

.. note:: 

   Primitive descriptor base constructed this way does not support :ref:`next_impl() <doxid-structdnnl_1_1primitive__desc_1a841df469ca54c3de2d233e46f48322b2>` (will throw).



.. rubric:: Parameters:

.. list-table::
	:widths: 20 80

	*
		- pd

		- C API primitive descriptor to clone.

	*
		- prim_kind

		- Expected primitive kind.

	*
		- prop_kind1

		- Expected propagation kind (option 1).

	*
		- prop_kind2

		- Expected propagation kind (option 2). This value is checked if the check with ``prop_kind1`` fails.